The present invention relates to the field of construction, of public works and civil engineering, in particular the sealing of works, and has for its object a resinous composition with improved adhesive properties, as well as its use, in particular for sealing road work.
Seals in construction and public works are often made, particularly for flat horizontal surfaces, of membranes or bituminous sheets fixed on the support by partial melting of their undersurface to obtain intimate and resistant adherence.
However, the use of burners or similar heating apparatus in certain regions of the surfaces to be covered adjacent openings can transmit flames, inflammable elements or loose material can give rise to the risk of the beginning of burning during the application of the flame or, even worse, the risk of burning after the work, by reactivation of the combustion of the slowly combustible materials having been in contact with the flame, such as for example thermal insulating materials, often hidden and covered by other materials less sensitive to heat.
There are of course also known sealing sheets with a cold self-adhesive undersurface, however they are difficult to emplace from a standpoint of coming unfastened and do not give rise to sufficiently great adherence to supply an intimate surface contact and a securement that is resistant over time, especially on inclined or vertical surfaces.
There also exist liquid or viscous sealing products, particularly bitumen based, that can be easily applied with a spatula or a brush, particularly at places where the installation of sheets is difficult.
Nevertheless, these liquid or viscous products often have insufficient elasticity to resist without damage the movements or deformations of the support, an unstable sealing over the course of time, poor resistance to UV and, above all, insufficient adhesivity to ensure sufficiently intimate, resistant and durable fastening on different supports, particularly inclined or vertical supports.
It is thus often necessary, in order to use these known liquid or viscous products, to provide a primary adhesion and/or a specific supplemental protective layer.
Finally, there are already known liquid sealing products in the form of bitumen/polyurethane mixtures, integrating large quantities of plastifiers, generally in the form of aromatic oils, and/or of fillers or liquid diluents.
However, these products, described for example in U.S. Pat. Nos. 5,319,008 and 4,871,792, have particularly a limited lifetime, the bitumen support or supports being attacked by oil, and this latter, as well as the filler or the liquid diluent, weakening the prepolymers of polyurethane used in these products, generating micro-cracks in the layer of applied product with a relatively short lifetime.
Moreover, these known products have a relatively limited strength of adhesion, requiring necessarily a specific protection against UV and having a relatively low resistance to chemical attack resulting from atmospheric agents, rendering hazardous their use on external or exposed sites, excluding a ten-year life outside and limiting their use to protected sites.
Moreover, the presence of large quantities of plastifiers and diluents, relative to the quantity of bitumen, results in a high cost.
Finally, these known bitumen/polyurethane mixtures are not used and cannot be used in monocomponent form, which would greatly facilitate their use, in particular at work sites.
The present invention has particularly for its object to overcome the mentioned drawbacks and to provide a product of the bitumen/polyurethane type, easy to use, tolerating a high proportion of bituminous mixture in its composition, having high strength and resistance and durable for unprotected outdoor use and requiring no primary adhesive layer, no matter what the nature of the support to which applied.
To this end, it has for its object a resonance monocomponent composition with improved adhesive properties, based on a bitumen/polymer base of polyurethane and adapted to constitute a sealing layer or a portion of a sealing layer, characterized in that the molecules of polyurethane prepolymer comprise at least one segment or group comprising at least 30 atoms of purely hydrogenated carbon.